u.s. nuclear weapons capability

461The Heritage Foundation | heritage.org/Military

U.S. Nuclear Weapons Capability

In today’s rapidly changing world, the U.S. nuclear weapons enterprise must be, in

the words of President Donald Trump, “mod-ern, robust, flexible, resilient, ready and appro-priately tailored to deter 21st-century threats and reassure our allies.”1 If the U.S. detects a game-changing nuclear weapons development in another country, the nuclear weapons com-plex must be able to provide a timely response.

After shifting focus away from maintaining nuclear dominance following the Cold War, the U.S. nuclear enterprise must again focus on its main mission. If it is going to continue its policy of deterrence through strength and assure its allies while promoting nuclear non-proliferation, the U.S. must overcome multiple challenges: an aging nuclear stockpile, aging infrastructure, and aging experts combined with an uncertain funding environment and issues surrounding overall force readiness.

The U.S. maintains an inactive stockpile that includes near-term hedge warheads that can be put back into operational status within six to 24 months. Extended hedge warheads purportedly can be made ready within 24 to 60 months.2 The U.S. preserves upload capability on its strategic delivery vehicles, which means that in principle, the nation could increase the number of nuclear warheads on each type of its delivery vehicles if contingencies warrant. For example, the U.S. Minuteman III intercon-tinental ballistic missile (ICBM) can carry up to three nuclear warheads, although it is cur-rently deployed with only one.3

While the United States preserves these capabilities, increasing capacity would be not only costly, but also difficult and

time-consuming in practice. Certain modern-ization decisions (e.g., 12 instead of 14 Colum-bia-class ballistic missile submarines, with 16 missile tubes per submarine instead of 24) will limit upload capacity on the strategic subma-rine force. U.S. heavy bombers will continue to retain a robust upload capability.

Presidential Decision Directive-15 (PDD-15) requires the U.S. “to maintain the ability to conduct a nuclear test within 24-to-36 months of direction by the President to do so.”4 Howev-er, successive governmental reports have not-ed the continued deterioration of technical and diagnostics equipment and the inability to fill technical positions supporting nuclear testing readiness.5 A lack of congressional support for improvements in technical readiness further undermines efforts by the National Nuclear Security Administration (NNSA) to comply with the directive.

The nuclear weapons labs face demograph-ic challenges of their own. Most scientists and engineers with practical hands-on experience in nuclear weapon design or testing experience (or both) are retired. This means that the U.S. must rely on the scientific judgment of design-ers and engineers who were involved neither in nuclear tests nor in weapons design and devel-opment and who must now continue to certify weapons designed and tested over 30 years ago.

Not all of the existing inactive stockpile will go through life-extension programs (LEPs). Hence, the U.S.’s ability to respond to contin-gencies by uploading weapons kept in an inac-tive status will decline with the passage of time. This means that even with LEPs, the U.S. may not be able to sustain the necessary reliability.

462 2020 Index of U.S. Military Strength

After the end of the Cold War, the shift in emphasis away from the nuclear mission caused the nuclear laboratories to lose a sense of purpose. They felt compelled to reorient and broaden their mission focus. According to a number of studies, their relationship with the government also evolved in ways that reduced output and increased costs. The NNSA was supposed to address these problems but has largely failed in this task, partly because “the relationship with the NNSA and the National security labs appears [to] be broken.”6

In 1999, the Commission on Maintaining U.S. Nuclear Weapons Expertise concluded

that 34 percent of the employees supplying critical skills to the weapons program were more than 50 years old. Almost 19 percent of the NNSA’s workforce is eligible for retirement, and the number will likely increase to 38.5 per-cent in fiscal year (FY) 2023.7 On average, the U.S. high-technology industry has a more bal-anced employee age distribution.8

Both the lack of resources and the lack of sound, consistent policy guidance have un-dermined workforce morale. The Congressio-nal Advisory Panel on the Governance of the Nuclear Security Enterprise recommended fundamental changes in the nuclear weapons

0

10

20

30

40

50

’192010200019901980197019601950

TYPES OF WARHEADS IN THE U.S. NUCLEAR STOCKPILE

TOTAL WARHEADS IN THE U.S. NUCLEAR STOCKPILE

2019: 11

1989: 28

1963: 51

0

5,000

10,000

15,000

20,000

25,000

30,000

’192010200019901980197019601950

2019: 3,800

1988: 23,205

1967: 31,255

CHART 13

A Smaller and Less Diverse Nuclear Arsenal

A heritage.org

SOURCES: Robert S. Norris and Hans M. Kristensen, “U.S. Nuclear Warheads, 1945–2009,” Bulletin of the Atomic Scientists, 2009, https://www.tandfonline.com/doi/full/10.2968/065004008 (accessed April 20, 2018); U.S. Department of Energy, Report to Congress, “Stockpile Stewardship and Management Plan,” November 2017, https://www.energy.gov/sites/prod/files/2017/11/f46/ fy18ssmp_final_november_ 2017%5B1%5D_0.pdf (accessed April 23, 2018); U.S. Department of Energy, “Restricted Data Declassification Decisions, 1946 to the Present,” https://fas.org/sgp/library/rdd-5.html (accessed April 23, 2018); U.S. Department of Defense, “Stockpile Numbers,” http://open.defense.gov/Portals/23/Documents/frddwg/2017_Tables_ UNCLASS.pdf (accessed April 23, 2018); Hans M. Kristensen and Matt Korda, “United States Nuclear Forces, 2019,” Bulletin of the Atomic Scientists, April 29, 2019, https://www.tandfonline.com/doi/pdf/10.1080/00963402.2019.1606503?needAccess=true (accessed July 11, 2019); and Hans M. Kristensen and Matt Korda, “Status of World Nuclear Forces,” May 2019, https://fas.org/issues/nuclear-weapons/ status-world-nuclear-forces/ (accessed July 11, 2019).


1945 1950 1955 1960 1965 1970 1975

1945 1950 1955 1960 1965 1970

1975

1980 1985

1980 1985 1990 1995 2000 2005 2010 2015

1990 1995 2000 2005 2010 2015

The bulk of the current nuclear arsenalwas first developed in the 1980s.

From 1989 through 1992, 17 types of nuclear weapons were taken out of operation. Those 17 types totaled more than 24,000 nuclear warheads during their operational periods.

In 1976, the last 10+ megaton warhead was taken out of operation.

The Air Force’s B53 bomb was operational for 43 years.

Combined, the W68and B28

comprised nearly 10,000

warheads.

2,000

4,000

0

OperationalPeriod

Number Built

Yield megatons

10 10

A heritage.org

SOURCES: Robert S. Norris and Hans M. Kristensen, "U.S. Nuclear Warheads, 1945–2009," Bulletin of the Atomic Scientists, 2009, https://www.tandfonline.com/ doi/full/10.2968/065004008 (accessed April 20, 2018), and U.S. Department of Energy, Report to Congress, “Stockpile Stewardship and Management Plan,” November 2017, https://www.energy.gov/sites/prod/ files/2017/11/f46/fy18ssmp_final_november_2017% 5B1%5D_0.pdf (accessed April 23, 2018).

CHART 14

A Brief History of the Shrinking U.S. Nuclear Arsenal


enterprise’s culture, business practices, project management, and organization. Others pro-posed moving the NNSA to the Department of Defense (DOD).9

The U.S. nuclear laboratories must redis-cover their mission focus so that they can be ready to meet the challenges that lie ahead.

The readiness of forces that operate U.S. nu-clear systems is another important indication of the health of the overall force. Despite the changes instituted by the Air Force following mishaps in 2006 and 2007, success was limited, as evidenced by further mishaps. In January 2014, for example, the Air Force discovered widespread cheating on nuclear proficiency exams and charged over 100 officers with mis-conduct. The Navy had a similar problem, al-beit on a smaller scale.10

The DOD conducted two nuclear enterprise reviews, one internal and one external. Both reviews identified a lack of leadership atten-tion, a lack of resources with which to modern-ize the atrophied infrastructure, and unduly burdensome implementation of the personnel reliability program as some of the core chal-lenges preventing a sole focus on accomplish-ing the nuclear mission.11

In 2014, the Secretary of Defense created the Nuclear Deterrent Enterprise Review Group (NDERG) to ensure the long-term health of the nuclear enterprise by addressing resourc-ing, personnel, organizational, and enterprise policy issues. In the past several years, the DOD has significantly improved morale throughout the nuclear weapons enterprise by forcefully stating (and at the highest levels) that nuclear deterrence is the DOD’s “number one job” and that related modernization programs still re-ceive the highest priority. Recently, the Gov-ernment Accountability Office found that the DOD not only has made significant progress in implementing the recommendations from the 2014 nuclear enterprise reviews and a 2015 NC3 review, but also has improved its tracking and evaluation of this progress.12

Among other things, the ICBM Force Im-provement Program was initiated and mostly implemented throughout 2014 and into 2015,

and the Air Force shifted over $160 million to address problems, modernize certain facilities, and generally improve morale. The Air Force also has seen an increase in badly needed man-power, although not enough of an increase to alleviate manpower concerns. If changes in the nuclear enterprise are to be effective, leaders across the executive and legislative branches must continue to provide the resources and attention needed to mitigate readiness and morale issues within the force.

In the past, fiscal uncertainty and a steady decline in resources for the nuclear weapons enterprise have had a negative effect on the nuclear deterrence mission. As David Tracht-enberg, Deputy Under Secretary of Defense for Policy, testified in March 2019:

For decades, the United States led the world in efforts to reduce the role and number of nuclear weapons…. Overall, the U.S. nuclear weapons stockpile has drawn down by more than 85 percent from its Cold War high.

Unfortunately Russia and China have cho-sen a different path and have increased the role of nuclear weapons in their strat-egies and actively increased the size and sophistication of their nuclear forces.

For this reason, a robust and modern U.S. nuclear deterrent helps ensure the United States competes from a position of strength and can deter nuclear attack and prevent large-scale conventional warfare between nuclear-armed states for the foreseeable future.13

In recent years, bipartisan congressional support for the nuclear mission has been strong, and additional funding has been pro-vided for nuclear modernization. It is critical that this bipartisan consensus be preserved as these programs mature and begin to introduce modern nuclear systems to the force.

The Trump Administration has inherit-ed an insufficiently funded comprehensive


modernization program for nuclear forces: warheads, delivery systems, and command and control. The Obama Administration included this program in its budget requests, and Con-gress has funded it to some extent while con-straining the ability of the enterprise to exe-cute its mission (e.g., by allocating inadequate funding for pit production). Because such modernization activities require consistent, stable, long-term funding commitments, it is essential that Congress continue to invest in the cornerstone of our nation’s security.

The Trump Administration’s 2018 NPR rec-ognized worsening security conditions, the rise of competition with a revisionist and resurgent Russia, an increasingly threatening China, and other growing strategic threats.14 It also called for the tailoring of U.S. nuclear deterrence strategies and rearticulated the importance of deterring any large-scale attack against the U.S., its allies, or partners as a key priority of U.S. nuclear weapons policy. To that end, the 2018 NPR called for modernization of nuclear weapons and the nuclear weapons complex, as well as significant reinvestments in the nuclear triad (intercontinental-range ballistic missiles, Columbia-class submarines, bombers, and as-sociated infrastructure), and proposed two additional nuclear capabilities: a low-yield warhead for strategic submarine-launched bal-listic missiles (SLBMs) in the near term and a low-yield, nuclear-armed, sea-launched cruise missile in the longer term.

Implications for U.S. National SecurityU.S. nuclear forces are not designed to

shield the nation from all types of attacks from all adversaries. They are designed to deter large-scale attacks that threaten America’s sov-ereignty, allies, and forward-deployed troops and to assure our allies and partners.

U.S. nuclear forces play an absolutely es-sential role in underpinning the broad non-proliferation regime by providing security guarantees that assure allies, including NATO, Japan, and South Korea, that they can forgo de-velopment of nuclear capabilities. In part, U.S. deterrence capabilities also enable the United

Kingdom and France to limit their numbers of nuclear weapons to levels to which they might not otherwise agree.

North Korea has demonstrated that a country with limited intellectual and finan-cial resources can develop a nuclear weapon. Despite U.S. and international pressure, Iran appears to be continuing on a path that large-ly retains its ability to develop a nuclear weap-on capability. In such an international climate, U.S. nuclear assurances to allies and partners become ever more important. If the credibil-ity of American nuclear forces continues to degrade, for example, countries like Japan or South Korea could choose to pursue an inde-pendent nuclear option, adding to instability across the region.

Several negative trends could undermine the overall effectiveness of U.S. nuclear deter-rence if not addressed. Adversaries—particu-larly Russia and China—are modernizing their nuclear forces. Additional challenges include increasingly aged nuclear warheads; an aging and crumbling nuclear weapons infrastruc-ture; an aging workforce; and the need to fully recapitalize all three legs (land, air, and sea) of the nuclear triad, including the systems for nuclear command and control, while also con-ducting timely and cost-efficient life-extension programs—all while maintaining the nation’s commitment to a testing moratorium under the signed (but rejected by the Senate) Com-prehensive Test Ban Treaty.

The 2018 NPR notes a rapid deterioration of the threat environment since 2010 and identifies four enduring roles for U.S. nucle-ar capabilities:

l Deterring nuclear and non-nuclear attack;

l Assuring allies and partners;

l Achieving U.S. objectives if deterrence fails; and

l Providing the capacity to hedge against an uncertain future.15


Recognizing that capabilities can vary, the

2018 NPR emphasizes the need for tailored deterrence strategies to deal with each U.S. adversary. For example, Russia is engaged in an aggressive nuclear buildup, having added several new modern nuclear systems to its ar-senal since 2010. According to General John Hyten, Commander, U.S. Strategic Command (STRATCOM), “Russia started their modern-ization program in 2006. They’re about 80 percent through completing the moderniza-tion of their triad. They’ll be pretty close to being through by about 2020.”16 Concurrently, Russia is using its dual-capable (nuclear/con-ventional-capable) platforms to threaten the sovereignty of U.S. allies in Eastern Europe and the Baltics.

China is engaging in a similarly provocative nuclear buildup as it attempts to project pow-er into the South China Sea, in part through illegally created islands on which China has installed offensive capabilities. North Korea

“has accelerated its provocative pursuit of nu-clear weapons and missile capabilities.”17 Iran

“retains the technological capability and much of the capacity necessary to develop a nuclear weapon within one year of a decision to do so” and is the world’s principal state sponsor of terrorism.18

Deterrence is an intricate interaction be-tween U.S. conventional and nuclear forces and the psychological perceptions of both al-lies and adversaries with respect to the will-ingness of the U.S. to use such forces to de-fend its own interests and those of its allies and partners. Nuclear deterrence must reflect and be attuned to the mindset of any particu-lar adversary that the U.S. seeks to deter. If an adversary believes that he can fight and win a limited nuclear war, the task for U.S. leaders

is to convince that adversary otherwise. The U.S. nuclear portfolio must be structured in terms of capacity, capability, variety, flexibility, and readiness to achieve these objectives. In addition, military roles and requirements for nuclear weapons will be inherently different depending on which actor is being deterred, what that actor values, and what kinds of ac-tion the U.S. is seeking to deter.

Due to the complex interplay among strate-gy, policy, and actions that any given state may take, as well as other actors’ perceptions of the world around them, it is not possible to know whether and when a nuclear deterrent or con-ventional forces provided by U.S. forces might be perceived as insufficient. Nuclear weapon capabilities take years or decades to develop, as does the infrastructure supporting them—an infrastructure that the U.S. has neglected for decades. We can be reasonably certain that a robust, well-resourced, focused, and reliable nuclear enterprise is much more likely to maintain the sense of the U.S. as a deterring force than is one that is outdated, questionable, or both.

The U.S. has demonstrated that it is capable of incredible mobilization when danger mate-rializes. Today’s nuclear threat environment is evolving, dynamic, and proliferating in unpre-dictable ways, with new actors and resurgent old actors developing new capabilities. Mean-while, the U.S. enterprise remains largely stat-ic (despite the promise of additional funding) and likely at a technological disadvantage.

This posture is worrisome and must be changed. Unless it is fixed, the implications, both for the security of the United States and for the security of its allies and the free world, are extremely serious.

Scoring U.S. Nuclear Weapons CapabilitiesThe U.S. nuclear weapons enterprise is

composed of several key elements that include warheads; delivery systems; nuclear command and control; intelligence, surveillance, and

reconnaissance (ISR); aerial refueling; and the physical infrastructure that designs, man-ufactures, and maintains U.S. nuclear weapons. The nuclear enterprise also includes and must


sustain the talent of its people, from nuclear designers to engineers, manufacturing person-nel, securers, planners, maintainers, and oper-ators, all of whom can help to ensure a nuclear deterrent that is second to none.

At the same time, assessing whether any one piece of this enterprise is sufficiently funded, focused, and/or effective with regard to the U.S. nuclear mission presents several challenges.

First, the United States is not taking full advantage of technologically available devel-opments to field modern (often incorrectly referred to as “new”) warheads that could be designed to be safer, more secure, and more effective and that could give the United States better options for strengthening a credible de-terrent. Rather the U.S. has elected to largely maintain aging nuclear warheads—based on designs from the 1960s, 1970s, and 1980s—that were in the stockpile when the Cold War ended.

Second, the lack of detailed publicly avail-able data about the readiness of nuclear forc-es, their capabilities, and weapon reliability makes analysis difficult.

Third, the U.S. nuclear enterprise has many components, some of which are also involved in supporting other conventional military and extended deterrence missions. For example:

l Dual-capable bombers no longer fly airborne alert with nuclear weapons as they routinely did in the 1960s (although they are capable of resuming the practice if necessary).

l The three key national security labora-tories (Los Alamos National Laboratory, Lawrence Livermore National Laboratory, and Sandia National Laboratories) no longer focus solely on the nuclear weap-ons mission. Although this remains their primary mission, they also perform exten-sive national security research related to nuclear nonproliferation, counterprolif-eration, intelligence, biological/medical research, threat reduction, and counter-ing nuclear terrorism, including a variety of nuclear-related detection activities.

l The Nuclear Command, Control, and Communications (NC3) system “performs five crucial functions: detection, warning, and attack characterization; adaptive nu-clear planning; decision-making confer-encing; receiving Presidential orders; and enabling the management and direction of forces.”19

The factors listed and explained below are the most important elements of the nuclear weapons complex. They are judged on a five-grade scale according to which “very strong” means that a sustainable, viable, and funded plan is in place and “very weak” means that the U.S. is not meeting its security requirements and has no program in place to redress the shortfall—a situation that if left uncorrected could seriously damage vital national interests. The other three possible scores are “strong,”

“marginal,” and “weak.”

Current U.S. Nuclear Stockpile Score: Strong

U.S. warheads must be safe, secure, effec-tive, and reliable. The Department of Energy (DOE) defines reliability as “the ability of the weapon to perform its intended function at the intended time under environments con-sidered to be normal” and as “the probability of achieving the specified yield, at the target, across the Stockpile-to-Target Sequence of en-vironments, throughout the weapon’s lifetime, assuming proper inputs.”20 In the years since the cessation of nuclear testing in 1993, reli-ability has been determined through an inten-sive warhead surveillance program; non-nu-clear experiments (that is, without the use of experiments producing nuclear yield); sophis-ticated calculations using high-performance computing; and related annual assessments and evaluations.

The reliability of nuclear warheads and de-livery systems becomes even more important as the number and diversity of nuclear weap-ons in the stockpile decrease. Possession of fewer types of nuclear weapons means a small-er margin for error in the event that all of one


type is affected by a technical problem that might cause that type of weapon, its delivery system, or both to be decommissioned. Less diversity also means that a problem is more likely to affect multiple systems. America and its allies must have high confidence that U.S. nuclear warheads will perform as expected.

As warheads age, our uncertainty about their ability to perform their mission as ex-pected could increase, significantly complicat-ing military planning. Despite the impressive knowledge about nuclear weapons physics and materials chemistry that it has amassed, the U.S. could find itself surprised by unanticipat-ed long-term effects on aging components of nuclear weapons. “The scientific foundation of assessments of the nuclear performance of US weapons is eroding as a result of the mor-atorium on nuclear testing,” argue John Hop-kins, nuclear physicist and a former leader of the Los Alamos National Laboratory’s nuclear weapons program, and David Sharp, former Laboratory Fellow and a guest scientist at Los Alamos National Laboratory.21

The United States currently has the world’s safest and most secure stockpile, but con-cerns about overseas storage sites, potential problems introduced by improper handling, or the unanticipated effects of aging could compromise the integrity and reliability of U.S. warheads. In addition, nuclear warheads themselves contain security measures that are designed to make it difficult, if not im-possible, to detonate a weapon without prop-er authorization.

Grade: The Department of Energy and De-partment of Defense are required to produce annual assessments of the nuclear stockpile’s reliability. Each of the three nuclear weapons labs (Los Alamos National Laboratory, Law-rence Livermore National Laboratory, and Sandia National Laboratories) reports its findings on the safety, security, and reliability of the nation’s nuclear warheads to the DOE and the DOD, which in turn brief the President. Detailed classified reports are also provided to Congress. While these assessments do not include the nuclear weapons delivery systems,

U.S. STRATCOM does assess the overall reli-ability of the U.S. nuclear weapons system, in-cluding both warheads and delivery platforms.

Absent nuclear weapons testing, the na-tional laboratories’ assessment of weapons reliability, based on the full range of surveil-lance, scientific, and technical activities car-ried out in the NNSA’s stockpile stewardship program, depends on the expert judgment of the laboratory directors, which, although it is based on experience and non-nuclear experi-mentation and extensive modeling and simu-lation, is inherently subjective. While certainly a well-educated opinion, it cannot substitute for objective data obtained through direct nu-clear testing.

Nuclear testing was used in the past to di-agnose potential problems with warheads and to certify the effectiveness of fixes to those problems. It was also used originally to certify today’s nuclear warheads, as well as to detect potential problems and to confirm the effec-tiveness of fixes to those problems. Given that modern simulation is based on nuclear tests that were conducted primarily in the 1950s and 1960s, using testing equipment from that era, there is a great deal more that more mod-ern nuclear testing and detection equipment could teach us about nuclear weapons physics.

In 2005, according to one authoritative account, “two DoD study teams, each look-ing at options for the future nuclear stock-pile, reached similar conclusions—the U.S. approach to sustain its existing nuclear war-head stockpile needed to be redirected.”22 Continuing:

Both studies expressed concern over the prospect of long-term success of the plan to sustain the Cold War-era nuclear stockpile indefinitely through period-ic refurbishments (e.g., life extension programs). The indefinite refurbishment plan will be extremely difficult to execute (because many warhead components can not [sic] be replicated as originally built), and would result in modifications on top of other modifications that will be


increasingly difficult to certify without nuclear testing. Both studies concluded that the Reliable Replacement Warhead (RRW) concept, if feasible, would be a preferred alternative to the indefinite refurbishment strategy.23

When the U.S. did conduct nuclear tests, it frequently found that small changes in a weapon’s tested configuration had a dramatic impact on weapons performance. In fact, the 1958–1961 testing moratorium resulted in the introduction of weapons with serious prob-lems into the U.S. stockpile.24 These problems were discovered only after the resumption of U.S. nuclear weapons testing after the Soviet Union’s unannounced breakout from the 1962 agreed moratorium.

America’s commitment to sustaining its nu-clear stockpile without nuclear testing creates inherent uncertainty concerning the adequacy of “fixes” to the stockpile when problems are found. The number of additional uncertain-ties is growing and includes updates made to correct problems that were found in the weap-ons or changes in the weapons resulting from life-extension programs. It is simply impossible to duplicate exactly weapons that were designed and built many decades ago. According to Dr. Stephen Younger, Director of Sandia National Laboratories, “[we have had to fix] a number of problems that were never anticipated” by using

“similar but not quite identical parts.”25

One of the results of having to certify weap-ons without nuclear testing, at least to date, has been fewer types of weapons (i.e., reduced diversity in the stockpile) and, consequently, a greater potential impact across the inventory of warheads should there be an unknown or misidentified error in the certification process. Loss of diversity in the stockpile also increases the risk that “common-mode” failure might af-fect multiple systems simultaneously, making the push for commonality with potential single points of failure in U.S. warheads worrisome.

“To be blunt,” warned Secretary of Defense Robert Gates in October 2008, “there is ab-solutely no way we can maintain a credible

deterrent and reduce the number of weapons in our stockpile without either resorting to testing our stockpile or pursuing a modern-ization program.”26

The U.S. is pursuing warhead life-extension programs that replace aging components be-fore they can cause reliability problems. The number and scope of LEPs being carried out over the next two decades will stress the NN-SA’s warhead design and production complex and remains a concern, particularly given un-certainties regarding the congressional budget process. In spite of these concerns, in FY 2018 and FY 2019, the NNSA continued to assert that the stockpile “remains safe, secure, and reliable” (FY 2018) and “safe, secure, and ef-fective” (FY 2019).27

In light of our overall assessment, we grade the U.S. stockpile conditionally as “strong,” subject to continued strong support from Con-gress and the Administration.

Reliability of U.S. Delivery Platforms Score: Marginal

Reliability encompasses not only the war-head, but strategic delivery vehicles as well. For ICBMs and SLBMs, in addition to a successful missile launch, this includes the separation of missile boost stages, performance of the mis-sile guidance system, separation of the reentry vehicles from the missile post-boost vehicle, and accuracy of the final reentry vehicle in reaching its target.28

The U.S. conducts flight tests of ICBMs and SLBMs every year to ensure the reliability of its delivery systems with high-fidelity “mock” warheads. Anything from faulty electrical wir-ing to booster separations could degrade the reliability and safety of the U.S. strategic de-terrent. U.S. strategic long-range bombers also regularly conduct continental United States and intercontinental exercises and receive upgrades to sustain a demonstrated high level of combat readiness. Nevertheless, challeng-es are on the horizon as platforms have to be modernized and replaced simultaneously and with little margin for error to allow for already significantly diminished gaps in capabilities.


Grade: The Air Force picked up the pace of

its ICBM testing last year relative to the pre-viously covered period. With four successes during the covered period, the Air Force also suffered its first unsuccessful ICBM test since 2001. The SLBM tests were successful in 2018 and 2019. To the extent that data from these tests are publicly available, they provide objec-tive evidence of the delivery systems’ reliabili-ty and send a message to U.S. allies and adver-saries alike that the U.S. system works and the nuclear deterrent is ready if needed. The aged systems, however, occasionally have reliability problems, as evidenced by a July 2018 failed Minuteman III launch.29

Overall, this factor earns a grade of “margin-al,” the same grade as the previous year’s score.

Nuclear Warhead Modernization Score: Marginal

During the Cold War, the United States maintained a strong focus on developing new nuclear warhead designs, both to counter So-viet advances and modernization efforts and to leverage advances in the physics, chem-istry, and design of nuclear weapons. Today, although it also seeks to retain the skills and capabilities required to design, develop, and produce new warheads, the United States is fo-cused on sustaining its aging stockpile rather than on fielding new nuclear warheads. This could increase the risk of failure due to aging components and signal to adversaries that the United States is less committed to nucle-ar deterrence.

In FY 2016, the United States established the Stockpile Responsiveness Program (SRP) and charged it with building up and exercis-ing all capabilities needed to “conceptualize, study, design, develop, engineer, certify, pro-duce, and deploy nuclear weapons.”30 The Ad-ministration requested $34 million for the SRP in FY 2019.

New weapon designs could allow American engineers and scientists to improve previous designs and devise more effective ways to ad-dress existing military requirements (e.g., the need to destroy deeply buried and hardened

targets) that have emerged in recent years. Fu-ture warheads could improve reliability (e.g., by remedying such ongoing aging concerns as the need to replace aged nuclear components) while also enhancing the safety and security of American weapons.

Working on new weapon design options would help to ensure that America’s nuclear experts remain engaged and knowledgeable, would help to attract the best talent to the nuclear enterprise, and would help the nation gain additional insights into adversaries’ nu-clear weapons programs. Merely updating Cold War designs is not enough to constrain poten-tial adversaries and current and future prolif-erators of nuclear technology, all of whom can seek designs apart from those of the U.S.

As the Panel to Assess the Reliability, Safe-ty, and Security of the United States Nucle-ar Stockpile noted, “Only through work on advanced designs will it be possible to train the next generation of weapon designers and producers. Such efforts are also needed to ex-ercise the DoD/NNSA weapon development interface.”31 The nuclear enterprise was able to display improved flexibility when it produced a low-yield version of the W76-2 warhead de-signed to counter Russia’s perception of an exploitable gap within the U.S. nuclear force posture within a year. Other nations main-tain their levels of proficiency by having their scientists work on new nuclear warheads and possibly by conducting very low-yield nuclear weapons tests.32

Grade: Despite continued nuclear policy restrictions and a preference for life-exten-sion programs, U.S. efforts under the SRP and the NNSA’s demonstrated ability to produce a low-yield version of the W76-2 warhead in a timely manner warrant improving this score to “marginal” this year. The success of the SRP will be an important consideration in fu-ture assessments.

Nuclear Delivery Systems Modernization Score: Strong

Today, the United States fields a triad of nuclear forces with delivery systems that are


safe and reliable, but as these systems age, the risk of a significantly negative impact on opera-tional capabilities increases, and any allowance for delay of platform replacement is signifi-cantly diminished. Age degrades reliability by increasing the potential for systems to break down or fail to respond correctly. The older weapons systems are, the more at risk they are that faulty components, malfunctioning equip-ment, or technological developments will limit their reliability in the operating environment.

Corrupted systems, defective electron-ics, or performance degradation due to long-term storage defects (including for nuclear warheads) can have serious implications for American deterrence and assurance. Because it cannot be assumed (especially with respect to systems approaching end of life) that a strate-gic delivery vehicle will always operate reliably, that vehicle’s deterrence and assurance value may be significantly reduced, with consequent impact on the deterrence perceptions of both allies and adversaries.

The U.S. Air Force and Navy plan to mod-ernize or replace each leg of the nuclear triad in the next few decades, but fiscal constraints, inconsistent levels of funding, and issues relat-ed to “continuing resolutions” will make such efforts difficult at best. Sustained leadership focus is imperative if the modernization pro-gram is to succeed.

The Navy is fully funding its programs to replace the Ohio-class submarine with the Columbia-class submarine, but issues early in the program that were identified last year have caused the margin for slippage in the overall schedule of the program itself to decrease.33 The Air Force is funding the B-21 Raider long-range bomber. Existing ICBMs and SLBMs are expected to remain in service until 2032 and 2042, respectively.

Remanufacturing some weapon parts is dif-ficult and expensive either because the manu-facturers are no longer in business or because the materials that constituted the original weapons are no longer available (e.g., due to environmental restrictions). Modernization of the U.S. triad is a requirement validated by all

four of the NPRs since the end of the Cold War and will remain a must in all future deterrence scenarios. Plans for modernization of U.S. nu-clear weapons benefited from the predictabili-ty associated with the FY2018/FY 2019 budget deal, but the return of sequestration threatens this progress.

The ability of the U.S. to produce sufficient numbers of solid-fuel rocket engines and pos-sible U.S. dependence on Russia as a source of such engines are other significant long-range concerns.34

Grade: U.S. nuclear platforms are in dire need of recapitalization. Plans for moderniza-tion of the nuclear triad are in place, and Con-gress and the services have largely sustained funding for these programs, notwithstanding difficulties caused by the Budget Control Act of 2011. This demonstration of commitment to nuclear weapons modernization earns this indicator a grade of “strong,” although possible delays in modernization could cause this score to be downgraded in the near future.

Nuclear Weapons Complex Score: Marginal

Maintaining a reliable and effective nuclear stockpile depends in large part on the facili-ties where U.S. devices and components are developed, tested, and produced. These facili-ties constitute the foundation of our strategic arsenal and include the:

l Los Alamos National Laboratory,

l Lawrence Livermore National Laboratory,

l Sandia National Laboratories,

l Nevada National Security Site,

l Pantex Plant,

l Kansas City Plant,

l Savannah River Site, and

l Y-12 National Security Complex.


In addition to these government sites, the

defense industrial base supports the devel-opment and maintenance of American deliv-ery platforms.

These complexes design, develop, test, and produce the weapons in the U.S. nuclear arse-nal, and their maintenance is of critical impor-tance. As the 2018 NPR states:

An effective, responsive, and resilient nuclear weapons infrastructure is essen-tial to the U.S. capacity to adapt flexibly to shifting requirements. Such an infra-structure offers tangible evidence to both allies and potential adversaries of U.S. nuclear weapons capabilities and thus contributes to deterrence, assurance, and hedging against adverse developments. It also discourages adversary interest in arms competition.35

Maintaining a safe, secure, effective, and reliable nuclear stockpile requires modern facilities, technical expertise, and tools both to repair any malfunctions quickly, safely, and securely and to produce new nuclear weapons if required to do so. The existing nuclear weap-ons complex, however, is not fully functional. The United States, for example, has not had a substantial plutonium-pit production capa-bility since 1993. A plutonium pit is the heart of a nuclear weapon, and the NNSA currently plans to produce no fewer than 80 pits a year by 2030—a challenge by its own admission.36 In 2005, it was reported that the U.S. cannot

“serially produce many crucial components of our nuclear weapons.”37

If the facilities are not properly funded, the U.S. will gradually lose the ability to conduct the required high-quality experiments that are needed to ensure the stockpile’s reliability without nuclear testing. In addition to demor-alizing the workforce and hampering recruit-ment, old and/or obsolete facilities and poor working environments make maintaining a safe, secure, reliable, and militarily effective nuclear stockpile difficult. Upwards of 50 per-cent of the NNSA’s facilities are more than 40

years old, nearly 30 percent date to the Man-hattan Project of the 1940s, and 12 percent are considered excess or no longer needed.38 The NNSA reported $2.5 billion in deferred main-tenance as of February 2019.39

The U.S. currently retains over 5,000 old plutonium pits in strategic reserve in addi-tion to pits for use in future LEPs. There are disagreements as to the effect of aging on plu-tonium pits and on how long the U.S. will be able to depend on them before replacement. In 2006, then-NNSA Administrator Linton Brooks estimated that the life span of warhead plutonium is “somewhere between 45 and 60 years,” which means that in the near future, the United States may have to start replacing core components of its nuclear warheads.40

Current capacities to do so are insufficient because the U.S. has demonstrated an ability to produce only about 10 plutonium pits a year at the Los Alamos PF-4 facility. If executed as planned, infrastructure modernization plans for PF-4 as mandated by the 2018 NPR will boost that number to about 30 by the middle of the next decade.

A second plutonium-pit production facili-ty is being planned to exploit the Mixed Oxide Fuel (MOX) facility that until last year was un-der construction at the Savannah River Plant in Tennessee. The MOX building is being re-purposed for a production capacity of no fewer than 50 plutonium pits per year to be achieved by 2030 for an overall requirement of no fewer than 80 pits per year. The challenge of achiev-ing this timeline is exacerbated by the fact that the NNSA is embarking on the most ambitious warhead sustainment program since the end of the Cold War, overhauling some five warhead types and stressing the demands on both work-force and facilities.

Manufacturing non-nuclear components can be extremely challenging either because some materials may no longer exist or because manufacturing processes have been forgotten and must be retrieved. There is a certain ele-ment of art to building a nuclear weapon, and such a skill can be acquired and maintained only through hands-on experience.


Grade: On one hand, the U.S. maintains

some of the world’s most advanced nuclear fa-cilities. On the other, some parts of the com-plex—importantly, the plutonium and highly enriched uranium component manufacturing infrastructure—have not been modernized since the 1950s. Plans for long-term infrastruc-ture recapitalization remain essential, even as the NNSA is embarking upon an aggressive warhead life-extension effort. Sustaining and/or increasing critically essential tritium gas is likewise essential because tritium gas is sub-ject to deterioration, and a delay in production increases the amount that must be produced to cover our baseline needs.

Significant progress has been made over the past year, however, both in recapitalizing uranium infrastructure and in getting funded plans in place to recapitalize plutonium-pit production capacity. The infrastructure is improved and therefore receives a grade of

“marginal.”

Personnel Challenges Within the National Nuclear Laboratories

Score: MarginalCombined with nuclear facilities, U.S. nu-

clear weapons scientists and engineers are critical to the health of the complex and the stockpile. The 2018 NPR emphasizes that:

The nuclear weapons infrastructure depends on a highly skilled, world-class workforce from a broad array of disci-plines, including engineering, the physical sciences, mathematics, and computer science. Maintaining the necessary critical skills and retaining personnel with the needed expertise requires sufficient op-portunities to exercise those skills.41

The ability to maintain and attract a high-quality workforce is critical to assuring the future of the American nuclear deter-rent, and hiring the best and brightest is es-pecially challenging in a strong employment atmosphere. Today’s weapons designers and

engineers are first-rate, but they also are ag-ing and retiring, and their knowledge must be passed on to the next generation of experts. This means that young designers need mean-ingful and challenging warhead design and de-velopment programs to hone their skills.

The SRP offers one visible means by which to address such concerns. The NNSA and its weapons labs understand this problem and, with the support of Congress, are beginning to take the necessary steps through SRP and foreign weapon assessment to mentor the next generation. To continue this progress, SRP funding will need to be sustained and ideally increased from the current rate of about $30 million a year.

The U.S. currently relies on non-yield-pro-ducing laboratory experiments, flight tests, and the judgment of experienced nuclear scientists and engineers, using robust modeling and sim-ulation, to ensure continued confidence in the safety, security, effectiveness, and reliability of its nuclear deterrent. Without their experience, the nuclear weapons complex could not func-tion. Few of today’s remaining scientists or engineers at the NNSA weapons labs have had the experience of taking a warhead from initial concept to a “clean sheet” design, engineering development, production, and fielding. The SRP is helping to remedy some of these short-falls by having the workforce exercise most of the skills required for nuclear weapons design and engineering.

The average age of the NNSA’s workforce decreased slightly to 47.8 years as of Septem-ber 2018.42 Still worrisome, however, is that over a third of this workforce will be eligible for retirement in the next four years. Given the distribution of workforce by age, these retire-ments will create a significant knowledge and experience gap.

Grade: In addition to employing world-class experts, the NNSA labs have had some success in attracting and retaining talent. As many scientists and engineers with practical nuclear weapon design and testing experience retire, the annual assessment and certification of nuclear weapons will rely increasingly on


the judgments of people who have never tested or designed a nuclear weapon. In light of these issues, the complex earns a score of “marginal,” albeit with signs of improvement.

Readiness of Forces Score: StrongThe people and units that operate U.S. de-

livery platforms are essential to the successful operation of America’s strategic forces. The military personnel operating the three legs of the nuclear triad must be properly trained and equipped, and the crews responsible for the nuclear mission must be maintained in an appropriate state of readiness.

During FY 2019, the services have contin-ued to align resources in order to preserve strategic capabilities in the short term. Nev-ertheless, a return to sequestration could have major negative effects on the timely execution of programs. U.S. general-purpose forces help to ensure the overall effectiveness of our nu-clear forces by, among other things, providing a pool of qualified candidates to operate nuclear weapon delivery systems. Changes prompted in part by the 2014 Navy and Air Force cheating scandals have addressed most morale issues and have recast the role of forces supporting the nuclear deterrent by providing addition-al funding for equipment purchases, creating more mid-career billets to help career-field continuity, focusing leadership attention, and changing training to focus on mission in the field rather than on a theoretical ideal. Sus-tained attention to the situation in the nuclear enterprise is critical.

Grade: Despite uncertainties regarding the future impact of budgetary shortfalls, the young men and women who secure, maintain, plan for, and operate U.S. nuclear forces are of extremely high caliber. Force readiness thus receives a grade of “strong.”

Allied Assurance Score: StrongThe credibility of U.S. nuclear deterrence

is one of the most important components of allied assurances. U.S. allies that already have nuclear weapons can coordinate actions with the United States or act independently. During

the Cold War, the U.S. and the United Kingdom cooperated to the point where joint targeting was included. France maintains its indepen-dent nuclear arsenal. The U.S. also deploys nu-clear gravity bombs in Europe as a visible man-ifestation of its commitment to its NATO allies.

Similarly, the U.S. has an enduring extended deterrence role with its Asian allies. The Unit-ed States provides nuclear assurances to Japan and South Korea, both of which are technolog-ically advanced industrial economies that face aggressive nuclear-armed regional adversaries such as China, Russia, and North Korea. Con-tinued assurances and guarantees of U.S. nu-clear deterrence must therefore be perceived as credible. Both Japan and South Korea have the capability and basic know-how to build their own nuclear weapons (even quickly) should they chose to do so. That would be a ma-jor setback for U.S. nonproliferation policies.

The 2018 NPR took a step in the right direc-tion when it placed “[a]ssurance of allies and partners” second on its list of four “critical roles” (immediately following “[d]eterrence of nuclear and non-nuclear attack”) that nuclear forces play in America’s national security strat-egy. The 2018 NPR proposed two supplements to existing capabilities—a low-yield SLBM war-head and a new nuclear sea-launched cruise missile—as important initiatives to strengthen assurance, along with the Obama and Trump Administrations’ initiatives to bolster conven-tional forces in NATO. Work on the low-yield warhead is progressing, and deployment of this capability will be an important factor in deterring aggression against America’s Asian and NATO allies in the years ahead.

Grade: At this time, most U.S. allies are not seriously considering developing their own nuclear weapons. European members of NATO continue to express their commitment to and appreciation of NATO as a nuclear al-liance even as they worry about the impact of Russia’s violations of the Intermediate Nuclear Forces Treaty and the regional implications of other arms control treaties, including the New Strategic Arms Reduction Treaty. Because uncertainties surrounding the purchase and


modernization of NATO’s dual-capable aircraft and the time line for replacing existing U.S. nu-clear weapons with the B61-12, as well as NA-TO’s seeming lack of attention to the nuclear mission and its intellectual underpinnings, do not justify a score of “very strong,” allied assur-ance receives a score of “strong.”

Nuclear Test Readiness Score: WeakIn the past, nuclear testing was one of the

key elements of a safe, secure, effective, and re-liable nuclear deterrent. Today, even though the U.S. is under a self-imposed nuclear testing moratorium, it is still required to maintain a low level of nuclear test readiness at the Ne-vada National Security Site (formerly Nevada Test Site).

“Test readiness” refers to a single test or a very short series of tests, not a sustained nuclear testing program, reestablishment of which would require significant additional resources. Specifically, under President Bill Clinton’s 1993 PDD-15, “[i]n order to resume underground nuclear tests, a capability to con-duct a nuclear test within 6 months up to FY 1996, and to conduct a nuclear test within 2–3 years after that time will be assumed by the De-partment of Energy [now NNSA].”43 Because of a shortage of resources, the NNSA has been unable to achieve this goal. The test readiness program is supported by experimental pro-grams at the Nevada National Security Site, nuclear laboratory experiments, and advanced diagnostics development.44

The ability of the U.S. to conduct yield-pro-ducing experiments in a timely manner if it should discover a flaw in one or more types of its nuclear weapons that requires exper-imentation to correct seems questionable. The U.S. might need to test to assure certain weapon characteristics that could possibly be validated only by nuclear testing and to verify render-safe procedures. The ability to con-duct yield-producing experiments rapidly is likewise important, especially if the U.S. needs to react strongly to another nation’s nuclear weapons tests and/or communicate unques-tioned resolve.

As noted, current law requires that the U.S. must maintain a capability to conduct a nuclear test within 24 to 36 months of a pres-idential decision to do so. The NNSA states in its Fiscal Year 2018 Stockpile Stewardship and Management Plan that its “fundamental approach taken to achieve test readiness has also changed” and lists a general time frame of six to 10 months for a simple test with waivers and simplified processes.45 The time frame “for a fully instrumented test to address stockpile needs with the existing stockpile” is 24 to 36 months, and “a test to develop a new capabil-ity” would take 60 months.46 A test within 18 months might be possible, “but only if ‘some domestic regulations, agreements and laws’ were to be waived.”47 Because the United States is rapidly losing its remaining practical nuclear testing experience, including instrumentation of very sensitive equipment, “there is essen-tially no test readiness,” and “[t]he whole test-ing process—whether to conduct one test or many—would in essence have to be reinvented, not simply resumed.”48

Grade: As noted, the U.S. can meet the le-gally required readiness requirement through the NNSA only if certain domestic regula-tions, agreements, and laws are waived. In addition, the U.S. is not prepared to sustain testing activities beyond a few limited exper-iments because it no longer retains the deep drilling technology in Nevada and has only a few “holes” capable of containing a nuclear test if required. Thus, testing readiness earns a grade of “weak.”

Overall U.S. Nuclear Weapons Capability Score: “Marginal” Trending Toward “Strong”

It should be emphasized that “trending toward ‘strong’” assumes that the U.S. main-tains its commitment to modernization of the entire enterprise, from warheads to platforms to personnel to infrastructure, and allocates needed resources accordingly. Absent this commitment, this overall score will degrade rapidly to “weak.” Continued attention to this mission is therefore critical.


Although a bipartisan commitment has

led to continued progress on the moderniza-tion of U.S. nuclear forces and sustainment of warheads, these programs remain seriously threatened by potential future fiscal uncertain-ties. The infrastructure that supports nuclear programs is very aged, and nuclear test read-iness has revealed troubling problems within the forces.

On the plus side, the 2018 NPR strong-ly articulates a core nuclear weapons policy grounded in the reality of today’s threats and growing international development concerns.

The 2018 NPR clearly and strongly articu-lates our continued commitment to extend-ed deterrence. The commitment to warhead life-extension programs, the exercise of skills that are critical for the development of new nuclear warheads under the SRP, and the just-in-time modernization of nuclear delivery platforms represent a positive trend that must be maintained.

Averaging the subscores across the nuclear enterprise in light of our concerns about the future results in an overall score of “marginal.”

U.S. Military Power: Nuclear

VERY WEAK WEAK MARGINAL STRONG VERY STRONG

Nuclear Stockpile %

Delivery Platform Reliability %

Warhead Modernization %

Delivery Systems Modernization %

Nuclear Weapons Complex %

National Labs Talent %

Force Readiness %

Allied Assurance %

Nuclear Test Readiness %

OVERALL %


Endnotes1. Quoted in U.S. Department of Defense, Office of the Secretary of Defense, Nuclear Posture Review 2018, February 2018, p. 1,

https://media.defense.gov/2018/Feb/02/2001872886/-1/-1/1/2018-NUCLEAR-POSTURE-REVIEW-FINAL-REPORT.PDF (accessed June 27, 2019).

2. “U.S. Nuclear Forces,” Chapter 3 in U.S. Department of Defense, Office of the Assistant Secretary of Defense for Nuclear, Chemical, and Biological Defense Programs, The Nuclear Matters Handbook, Expanded Edition, 2011, p. 39, https://www.ipndv.org/wp-content/uploads/2017/10/Nuclear_Matters_Handbook_2011.pdf (accessed June 27, 2019).

3. Center for Strategic and International Studies, Missile Defense Project, “Minuteman III,” Missile Threat, last updated June 15, 2018, https://missilethreat.csis.org/missile/minuteman-iii/ (accessed June 27, 2019).

4. “Test Readiness,” in Chapter 1, “Safety, Security, and Reliability of the U.S. Nuclear Weapons Stockpile,” in National Research Council, Committee on Reviewing and Updating Technical Issues Related to the Comprehensive Nuclear Test Ban Treaty, The Comprehensive Nuclear Test Ban Treaty: Technical Issues for the United States (Washington: National Academies Press, 2012), p. 30, http://www.nap.edu/openbook.php?record_id=12849&page=30 (accessed June 27, 2019).

5. Memorandum, “Report on the ‘Follow-up Audit of the Test Readiness at the Nevada Test Site,’” U.S. Department of Energy, Office of Inspector General, Audit Report No. OAS-L-10-02, October 21, 2009, http://energy.gov/sites/prod/files/igprod/documents/OAS-L-10-02.pdf (accessed June 27, 2019).

6. Dr. Charles V. Shank, Senior Fellow, Howard Hughes Medical Institute, and Co-chair, National Research Council Committee on Review of the Quality of the Management and of the Science and Engineering Research at the DOE’s National Security Laboratories–Phase 1, statement in Hearing to Receive Testimony on National Nuclear Security Administration Management of Its National Security Laboratories, Subcommittee on Strategic Forces, Committee on Armed Services, U.S. Senate, April 18, 2012, p. 5, http://www.armed-services.senate.gov/imo/media/doc/12-28%20-%204-18-12.pdf (accessed June 13, 2017).

7. Table, “Retirement Eligibility,” in U.S. Department of Energy, National Nuclear Security Administration, “National Nuclear Security Administration as of September 30, 2018,” https://www.energy.gov/sites/prod/files/2019/01/f58/201809%20NNSA%20workforce%20diversity%20statistics%20report.pdf (accessed April 10, 2019).

8. See chart, “Median Age of Employees Working at Selected Tech and Online Companies as of April 2016 (in Years),” Statista, last edited May 31, 2016, https://www.statista.com/statistics/653789/average-age-of-tech-company-employees/ (accessed July 26, 2019), and Robert Allen, “Average Age of Tech Company’s Employees [#ChartoftheDay],” Smart Insights, May 31, 2016, https://www.smartinsights.com/manage-digital-transformation/average-age-tech-companys-employees-chartoftheday/ (accessed July 26, 2019).

9. The report also recommends that the Department of Energy be renamed the “Department of Energy and Nuclear Security” to “highlight the prominence and importance of the Department’s nuclear security mission.” Congressional Advisory Panel on the Governance of the Nuclear Security Enterprise, A New Foundation for the Nuclear Enterprise: Report of the Congressional Advisory Panel on the Governance of the Nuclear Security Enterprise, November 2014, p. xii, http://cdn.knoxblogs.com/atomiccity/wp-content/uploads/sites/11/2014/12/Governance.pdf?_ga=1.83182294.1320535883.1415285934 (accessed June 27, 2019).

10. Kevin Liptak, “U.S. Navy Discloses Nuclear Exam Cheating,” CNN, updated February 4, 2014, http://www.cnn.com/2014/02/04/us/navy-cheating-investigation/index.html (accessed June 27, 2019).

11. See Section IV, “Underlying Issues: Leadership Focus, the Nuclear Enterprise Culture, Command Oversight, Investment—Visible Support, the Security Burden, and the Personnel Reliability Program,” in U.S. Department of Defense, Independent Review of the Department of Defense Nuclear Enterprise, June 2, 2014, pp. 21–38, https://dod.defense.gov/Portals/1/Documents/pubs/Independent-Nuclear-Enterprise-Review-Report-30-June-2014.pdf (accessed June 27, 2019).

12. U.S. Government Accountability Office, Defense Nuclear Enterprise: DOD Continues to Address Challenges but Needs to Better Define Roles and Responsibilities and Approaches to Collaboration, GAO-19-29, November 2018, https://www.gao.gov/assets/700/695197.pdf (accessed June 27, 2019).

13. David J. Trachtenberg, Deputy Under Secretary of Defense for Policy, statement in hearing, Fiscal Year 2020 Priorities for Department of Defense Nuclear Priorities, Subcommittee on Strategic Forces, Committee on Armed Services, U.S. House of Representatives, March 28, 2019, p. 1, https://armedservices.house.gov/hearings?ID=FA8DBDAB-5585-4437-AF88-61FBB1B7D428 (accessed June 27, 2019). In 2012, it was estimated that Russia can produce “about 2,000 new warheads each year.” Robert G. Joseph, “Second to One,” National Review, July 2, 2012, http://www.nationalreview.com/article/304310/second-one-robert-g-joseph (accessed June 28, 2019). According to an assessment published 10 years earlier, “a worst-case analysis (from the U.S. point of view) is that Russia could make 7,000 new warheads per year in a surge production.” Oleg Bukharin, “A Breakdown of Breakout: U.S. and Russian Warhead Production Capabilities,” Arms Control Association, October 2002, http://www.armscontrol.org/act/2002_10/bukharinoct02 (accessed June 28, 2019).


14. See, for example, Section II, “An Evolving and Uncertain International Security Environment,” in U.S. Department of Defense,

Office of the Secretary of Defense, Nuclear Posture Review 2018, pp. 5–14.

15. U.S. Department of Defense, Nuclear Posture Review, p. VII.

16. Testimony of General John E. Hyten, Commander, United States Strategic Command, in transcript, “U.S. Strategic Command and U.S. Northern Command SASC [Senate Armed Services Committee] Testimony,” U.S. Strategic Command, March 1, 2019, https://www.stratcom.mil/Media/Speeches/Article/1771903/us-strategic-command-and-us-northern-command-sasc-testimony/ (accessed June 28, 2019).

17. U.S. Department of Defense, Nuclear Posture Review, p. 11.

18. Ibid., p. 13.

19. U.S. Department of Defense, Office of the Secretary of Defense, Nuclear Posture Review 2018, p. XIII.

20. R. L. Bierbaum, J. J. Cashen, T. J. Kerschen, J. M. Sjulin, and D. L. Wright, “DOE Nuclear Weapon Reliability Definition: History, Description, and Implementation,” Sandia National Laboratories, Sandia Report No. SAND99-8240, April 1999, pp. 7–8, http://www.wslfweb.org/docs/usg/reli99.pdf (accessed June 28, 2019). Emphasis in original.

21. John C. Hopkins and David H. Sharp, “The Scientific Foundation for Assessing the Nuclear Performance of Weapons in the US Stockpile Is Eroding,” Issues in Science and Technology, Vol. XXXV, No. 2 (Winter 2019), p. 23, https://issues.org/wp-content/uploads/2019/01/Hopkins-Sharp-The-Scientific-Foundation-23-25-Winter-2019.pdf (accessed June 28, 2019).

22. Thomas Scheber, Reliable Replacement Warheads: Perspectives and Issues, United States Nuclear Strategy Forum Publication No. 0005 (Fairfax, VA: National Institute Press, 2007), p. 3, http://www.bits.de/NRANEU/docs/RRW07.pdf (accessed June 28, 22019).

23. Ibid., p. 4.

24. National Institute for Public Policy, The Comprehensive Test Ban Treaty: An Assessment of the Benefits, Costs, and Risks (Fairfax, VA: National Institute Press, 2011), pp. 24–25, http://www.nipp.org/wp-content/uploads/2014/12/CTBT-3.11.11-electronic-version.pdf (accessed June 28, 2019).

25. Stephen M. Younger, The Bomb: A New History (New York: HarperCollins, 2009), p. 192.

26. Robert M. Gates, speech delivered at Carnegie Endowment for International Peace, Washington, DC, October 28, 2008, http://archive.defense.gov/Speeches/Speech.aspx?SpeechID=1305 (accessed June 28, 2019). Emphasis in original.

27. U.S. Department of Energy, National Nuclear Security Administration, Report to Congress: Fiscal Year 2018 Stockpile Stewardship and Management Plan, November 2017, p. v, https://www.nukewatch.org/importantdocs/resources/fy18ssmp_final_november_2017.pdf (accessed June 28, 2019), and U.S. Department of Energy, National Nuclear Security Administration, Report to Congress: Fiscal Year 2019 Stockpile Stewardship and Management Plan—Biennial Plan Summary, October 2018, p. 1-8, https://www.energy.gov/sites/prod/files/2018/10/f57/FY2019%20SSMP.pdf (accessed June 28, 2019).

28. Robert W. Nelson, “What Does Reliability Mean?” in “If It Ain’t Broke: The Already Reliable U.S. Nuclear Arsenal,” Arms Control Association, corrected online August 29, 2008, https://www.armscontrol.org/act/2006_04/ReliableFeature (accessed June 28, 2019).

29. Joe Pappalardo, “The Air Force Destroyed an Unarmed Minuteman III ICBM During a Test Gone Wrong,” Popular Mechanics, July 31, 2018, https://www.popularmechanics.com/military/weapons/a22604568/air-force-minuteman-iii-icbm-test/ (accessed July 26, 2019).

30. U.S. Department of Energy, National Nuclear Security Administration, Report to Congress: Fiscal Year 2019 Stockpile Stewardship and Management Plan—Biennial Plan Summary, p. 1-16.

31. Panel to Assess the Reliability, Safety, and Security of the United States Nuclear Stockpile, Expectations for the U.S. Nuclear Stockpile Program: FY 2001 Report of the Panel to Assess the Reliability, Safety, and Security of the United States Nuclear Stockpile, 2002, p. 9, http://fas.org/programs/ssp/nukes/testing/fosterpnlrpt01.pdf (accessed June 28, 2019).

32. See, for example, Congressional Commission on the Strategic Posture of the United States, America’s Strategic Posture. The Final Report of the Congressional Commission on the Strategic Posture of the United States, 2009, p. 83, https://www.usip.org/sites/default/files/America’s_Strategic_Posture_Auth_Ed.pdf (accessed June 28, 2019).

33. “Officers Send Conflicting Signals on Columbia Sub Margin,” ExchangeMonitor, February 27, 2019, https://www.exchangemonitor.com/officers-send-conflicting-signals-columbia-margin/ (accessed April 15, 2019). Subscription required.

34. Sydney J. Freedberg Jr., “Fading Solid Fuel Engine Biz Threatens Navy’s Trident Missile,” Breaking Defense, June 16, 2014, http://breakingdefense.com/2014/06/fading-solid-fuel-engine-biz-threatens-navys-trident-missile/ (accessed June 28, 2019).

35. U.S. Department of Defense, Nuclear Posture Review Report, February 2018, p. xiv.


36. Rick Perry, Secretary of Energy, and Lisa E. Gordon-Hagerty, Under Secretary for Nuclear Security and Administrator of the

National Nuclear Security Administration, U.S. Department of Energy, statement in hearing, Department of Energy’s Atomic Energy Defense Programs, Committee on Armed Services, U.S. Senate, March 28, 2019, p. 2, https://www.armed-services.senate.gov/hearings/19-03-28-department-of-energys-atomic-energy-defense-programs (accessed June 28, 2019).

37. John S. Foster, Jr., “Nuclear Weapons and the New Triad,” in conference proceedings, Implementing the New Triad: Nuclear Security in Twenty-First Century Deterrence, Final Report, Institute for Foreign Policy Analysis and International Security Studies Program of the Fletcher School, Tufts University, December 14–15, 2005, p. 69. See also Amy F. Woolf, “Defense Primer: Strategic Nuclear Forces,” Congressional Research Service In Focus No. 10519, updated December 11, 2018, https://crsreports.congress.gov/product/pdf/IF/IF10519 (accessed July 26, 2019), p. 15., and Amy F. Woolf and James D. Werner, “The U.S. Nuclear Weapons Complex: Overview of Department of Energy Sites,” Congressional Research Service Report for Members and Committees of Congress, updated September 6, 2018, pp. 1 and 8, https://fas.org/sgp/crs/nuke/R45306.pdf (accessed July 26, 2019).

38. U.S. Department of Energy, National Nuclear Security Administration, Prevent, Counter, and Respond—A Strategic Plan to Reduce Global Nuclear Threats, FY 2017–FY 2021, March 2016, https://nnsa.energy.gov/sites/default/files/nnsa/inlinefiles/NPCR%20FINAL%203-31-16%20(with%20signatures).pdf (accessed June 13, 2017).

39. U.S. Department of Energy, National Nuclear Security Administration, “Infrastructure Modernization,” February 2019, https://www.energy.gov/sites/prod/files/2019/02/f59/2019-02-14-FACTSHEET-Infrastructure-Modernization.pdf (accessed June 28, 2019).

40. David Ruppe, “Research Suggests Warhead Plutonium Pits Last Longer,” Nuclear Threat Initiative, March 2, 2006, https://www.nti.org/gsn/article/research-suggests-warhead-plutonium-pits-last-longer/ (accessed June 28, 2019).

41. U.S. Department of Defense, Nuclear Posture Review, p. 63.

42. Table, “Age,” in U.S. Department of Energy, National Nuclear Security Administration, “National Nuclear Security Administration as of September 30, 2018.”

43. Presidential Decision Directive/NSC-15, “U.S. Policy on Stockpile Stewardship Under an Extended Moratorium and a Comprehensive Test Ban,” November 3, 1993, p. 5, https://fas.org/irp/offdocs/pdd/pdd-15.pdf (accessed June 29, 2019).

44. U.S. Department of Energy, National Nuclear Security Administration, Nevada National Security Site, “Stockpile Stewardship Program,” January 10, 2019, https://www.nnss.gov/pages/programs/StockpileStewardship.html (accessed June 29, 2019).

45. U.S. Department of Energy, National Nuclear Security Administration, Report to Congress: Fiscal Year 2018 Stockpile Stewardship and Management Plan, p. 3-26.

46. Ibid.

47. National Research Council, Committee on Reviewing and Updating Technical Issues Related to the Comprehensive Nuclear Test Ban Treaty, The Comprehensive Nuclear Test Ban Treaty: Technical Issues for the United States, p. 30.

48. John C. Hopkins, “Nuclear Test Readiness: What Is Needed? Why?” National Security Science, December 2016, p. 10, http://www.lanl.gov/discover/publications/national-security-science/2016-december/_assets/docs/NSS-dec2016_nuclear-test-readiness.pdf (accessed June 29, 2019).